Enhanced oil recovery is a process wherein an oil well that has suffered a decline in production due to depletion of the resources in the well and loss of reservoir pressure. Candidates for enhanced recovery are typically wells that have been in production for some time so that a significant volume of resources have been extracted from the well. In one type of enhanced oil recovery, a fluid is pumped into a reservoir to contact oil that does not flow at reservoir pressure. The fluid is typically designed to disperse the oil, reduce adhesion of the oil to reservoir structures, or otherwise ease movement of the oil out of the reservoir to the surface.
Many fluids used for enhanced recovery include surfactants and solvents. Such materials are typically blended with water obtained from reservoir structures to form a well injection fluid. The water is usually salty, making mixing with the solvents and surfactants challenging. In wells with high salinity brines, extractors often have to resort to expensive and time-consuming water treatment to reduce salinity and/or mineral hardness of the water. Thus, there is a need for well injection materials that are stable when mixed with high salinity well brines.